Before the course can teach how you measure something, it has to teach what you are holding — a small molecule, a large molecule, and an advanced therapy fail differently, are made differently, and demand entirely different definitions of “pure.”
Before any of the technique weeks make sense, the course needs to answer a question that has to come first: what is actually being made?
| Small molecule | Large molecule (biologic) | Advanced therapy | |
|---|---|---|---|
| Typical size | ~150–800 Da | ~150,000 Da (a mAb) | A virus, a lipid particle, or a cell |
| Made by | Defined organic synthesis, step by step — detail | Living cells (CHO, microbial) expressing a gene — detail | Transfection, transduction, or cell isolation and expansion — detail |
| What “the molecule” is | One defined structure | A population of closely related variants | An assembly (capsid + genome, particle + mRNA) or a living cell |
| Batch | Large, well-mixed, sampled | Large, from one bioreactor run | Can be a single patient’s dose |
| “Purity” | One number from one method | A panel of a dozen partly-independent attributes | Identity of an assembly; potency is often the hardest number |
| Defining instruments | UV-Vis, dissolution, HPLC/GC, MS, IR/Raman | ELISA, SPR/BLI, cell-based bioassay, SEC/CE-SDS/icIEF, peptide-mapping MS | Flow cytometry, ddPCR, NGS, rapid sterility |
| Where the course covers it | This week’s manufacturing sections, plus atomic and molecular spectroscopy, separations, specialized characterization, and mass spec | This week’s overview, with separations and MS applied cases in Week 8–10 | This week’s overview only |
The bottom rows are a thread the whole course pulls on: as a modality gets more complex, the “purity” question needs more methods to answer it, and each of those methods has to work harder to defend its own answer.
If you walk into a QC or analytical-development lab in this industry, the odds are strongly in favour of small molecule: tablets, capsules, and injectables built from defined organic synthesis still dominate the number of open analytical roles, which is why this course gives that column the most technique-week time and the other two their own depth here, up front, instead of spread across dedicated weeks. That is not a judgment about which modality matters more scientifically — it is a plain reflection of where the jobs are, and a course meant to get you ready for one should weight itself the same way.
Source note. The modality landscape follows standard pharmaceutical-technology and biopharmaceutical references; the jobs-market framing follows industry hiring-volume reporting (BioSpace, ACS C&EN annual employment surveys) rather than a single citable guideline. (Instructor: confirm current hiring-volume figures if citing numbers in lecture.)
The active pharmaceutical ingredient as a multi-step organic synthesis: route selection, why bench chemistry and plant chemistry are different disciplines, what changes — and what breaks — going from milligrams to tonnes, where ICH Q7 GMP begins in the route, and how the API’s final physical form sets up everything the next section does to it.
Turning the API powder into a tablet the patient can swallow: direct compression versus dry (roller-compaction) and wet (fluid-bed) granulation, compression and coating, and the packaging that protects what all of it achieved — bottles, foil blisters, and capsules — with each process choice justified against the API’s own properties and the stability / quality-by-design case behind it.
How the analytical toolkit scales up to biologics: recombinant manufacture and the control points along it, the monoclonal-antibody CQA panel, potency as a biological measurement, binding kinetics by SPR/BLI, particles and aggregation, and comparability (ICH Q5E) — the large-molecule column of the modality landscape, in depth.
The analytical frontier, taught with its two defining instruments in full: flow cytometry (principles, panel design, gating, and its use for CAR-T identity/purity/potency) and ddPCR (vector genome titre, vector copy number) — plus gene therapy (AAV, full/empty capsid), mRNA-LNP, oligonucleotides, and NGS. Where batch size shrinks toward one and the analyst defines the method and the specification at the same time as the product.